FxCop Rule CA2202 Do not dispose objects more than once

See the explanation in msdn:
http://msdn.microsoft.com/en-us/library/ms182334.aspx

Notice:

using( Stream stream = new FileStream(...))

{     

using(StreamWriter writer = new StreamWriter(stream))

  {         

  ....

  } 

}

this pattern the stream objects will be wrapped in the StreamWriter and will be disposed. In order that stream object will not be dispose more than once, we should write the following pattern:

Stream stream = null; 

try 

{     

 stream = new FileStream("file.txt", FileMode.OpenOrCreate);     

using(StreamWriter writer = new StreamWriter(stream))

  {        

      stream = null;         

      // Use the writer object...    

  }

 } 

finally 

{     

  if(stream != null)         

  stream.Dispose();

     // we dispose the stream object 

     //only it is not null 

}

We should remember this pattern.

Linq Query Take and Skip Extension Methods

var query=(from...

where...

select new {...}).Take(3);

Select the Top 3 elements.

var query=(from...

where...

select new {...}).Skip(2).Take(3);

Select the elements from 3 to 5. (Skip first 2, then select 3)

A WCF Binding Table (Reference, ZZ)

This is posted by Dan Rigsby, http://www.danrigsby.com/blog/index.php/2008/01/19/wcf-binding-comparision-list-and-supported-features-reference/

Name (Config Name) [Schemas]	Transport	Message Encoding	Message Version	Interop	Security	Session	Tx Flow	Duplex
BasicHttpBinding (basicHttpBinding) [http, https]	HTTP/HTTPS	Text	SOAP 1.1	Basic Profile 1.1	None, Transport, Message, Mixed	–	–	N
A binding that is suitable for communicating with WS-Basic Profile conformant Web services like ASP.NET Web services (ASMX)-based services.
WSHttpBinding (wsHttpBinding, webHttpBinding) [http, https]	HTTP/HTTPS	Text, MTOM	SOAP 1.2, WS-A 1.0	WS	None, Transport,Message, Mixed	None, Transport, Reliable Session	No, Yes(WS-AT)	N
A secure and interoperable binding that is suitable for non-duplex service contracts.
WS2007HttpBinding (ws2007HttpBinding) [http, https]	HTTP/HTTPS	Text, MTOM	SOAP 1.2, WS-A 1.0	WS-Security,WS-Trust,WS-SC, WS-SP	None, Transport,Message, Mixed	None, Transport, Reliable Session	No, Yes(WS-AT)	N
WSDualHttpBinding (wsDualHttpBinding) [http]	HTTP	Text, MTOM	SOAP 1.2, WS-A 1.0	WS	None,Message	Reliable Session	No, Yes(WS-AT)	Y
A secure and interoperable binding that is suitable for duplex service contracts or communication through SOAP intermediaries.
WSFederationHttpBinding (wsFederationHttpBinding) [http, https]	HTTP/HTTPS	Text, MTOM	SOAP 1.2, WS-A 1.0	WS-Federation	None,Message, Mixed	None, Reliable Session	No, Yes(WS-AT)	N
A secure and interoperable binding that supports the WS-Federation protocol, enabling organizations that are in a federation to efficiently authenticate and authorize users.
WS2007FederationHttpBinding (ws2007FederationHttpBinding) [http, https]	HTTP/HTTPS	Text, MTOM	SOAP 1.2, WS-A 1.0	WS-Federation	None,Message, Mixed	None, Reliable Session	No, Yes(WS-AT)	N
A secure and interoperable binding that derives from WS2007HttpBinding and supports federated security.
NetTcpBinding (netTcpBinding) [net.tcp]	TCP	Binary	SOAP 1.2	.Net	None,Transport, Message, Mixed	Transport, Reliable Session	No, Yes(OleTx)	Y
A secure and optimized binding suitable for cross-machine communication between WCF applications.
NetPeerTcpBinding (netPeerTcpBinding) [net.p2p]	P2P	Binary	SOAP 1.2	Peer	None,Transport, Message, Mixed	–	–	Y
A binding that enables secure, multi-machine communication.
NetNamedPipeBinding (netNamedPipeBinding) [net.pipe]	Named Pipe (IPC)	Binary	SOAP 1.2	.Net	None,Transport	None,Transport	No, Yes(OleTx)	Y
A secure, reliable, optimized binding that is suitable for on-machine communication between WCF applications.
NetMsmqBinding (netMsmqBinding) [net.msmq]	MSMQ	Binary	SOAP 1.2	.Net	None,Transport, Message, Both	–	No, Yes(OleTx)	N
A queued binding that is suitable for cross-machine communication between WCF applications.
MsmqIntegrationBinding (msmqIntegrationBinding)	MSMQ	*	–	MSMQ	None,Transport	–	No, Yes	N
A binding that is suitable for cross-machine communication between a WCF application and existing MSMQ applications.

*Doesn’t use a WCF message encoding – instead it lets you choose a pre-WCF serialization format
Notes: Items in bold are the defaults for features that have multiple values. “–“ = No Support
Abbreviations: WS-SC = WS-SecureConversation, WS-SP = WS-SecurityPolicy, WS-A = WS-Addressing, WS-AT = WS-AtomicTransaction, OleTx = OleTransactions

Feature	Description
Name	The name of the binding.
Config Name	The name of the binding used in configuration such as app.config or web.config.
Scheme	The supported Uri schemes.
Transport	The supported types of message transport (similar to Providers in Remoting).
Message Encoding	The supported types of message encoding.
Message Version	The supported message versions.
Interop	Names the protocol or technology with which the binding ensures interoperation.
Security	Specifies how the channel is secured: None: The SOAP message is not secured and the client is not authenticated. Transport: Security requirements are satisfied at the transport layer. Message: Security requirements are satisfied at the message layer. Mixed: This security mode is known as TransportWithMessageCredentials. It handles credentials at the message level, and integrity and confidentiality requirements are satisfied by the transport layer. Both: Both message level and transport level security are used. This ability is unique to the NetMsmqBinding.
Session	Specifies whether this binding supports session contracts.
Transaction Flow	Specifies whether transactions are enabled and the transaction flow type in ().
Duplex	Specifies whether duplex contracts are supported. Note this feature requires support for Sessions in the binding.